This application claims the priority of German Patent Application No. 101 48 534.4, filed Oct. 1, 2001, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a method for sensing the readiness of a driver to brake, in order to be able to generate adaptive warning times.
In known driver assistance systems, for example cruise controller with distance control, cornering warning or automatic driver lane detection or guiding, there are often critical situations in which the driver is warned or must very quickly assume control of the vehicle again and possibly brake quickly.
In known systems this is usually carried out by an audible warning signal. The prewarning time or the warning intensity is usually a constant parameter and is not adapted to the driver""s degree of attentiveness or readiness to act. This has the disadvantage that in many situations the warning comes too late or in many situations too early, which the driver experiences as an attempt to relieve him of control.
An object of the present invention is to specify a method for determining the readiness of the driver of a motor vehicle to brake. This method is also to make it possible to adapt the warnings, generated by a vehicle-mounted driver assistance system in the vehicle, to the readiness of the driver to brake.
This object is achieved according to the invention by the readiness of a motor vehicle driver to brake is determined by the position of the driver""s feet which is sensed by a sensor arrangement which senses the foot well of the motor vehicle to determine the position of the right-hand foot and left-hand foot of the driver and/or the leg posture of the driver.
In order to sense the feet and/or leg posture of the driver, a pressure-sensitive film with a matrix of pressure-sensitive cells can be arranged in the foot well of the motor vehicle. This film can easily be integrated into the foot mat.
Alternatively, photoelectric barriers can be arranged one next to the other so as to be interrupted by the driver""s feet in accordance with their position for sensing the feet and/or leg posture of the driver.
It is also contemplated to arrange infrared sensors in the foot well of the motor vehicle. The infrared sensors generate signals which sense the feet and/or leg posture of the driver by the triangulation method.
In accordance with a further development, an expected time t1 which the driver takes to activate the brake in a hazardous situation can be derived from the instantaneous position of the feet. The assessment as to whether a hazardous situation is present is performed by the vehicle-mounted driver assistance system. The prewarning time t2 of the vehicle-mounted driver assistance system can easily be adapted in accordance with the expected time t1.
The position of the driver""s feet and/or legs at a particular time can be evaluated, and a signal or coefficient which represents the readiness of the driver at a particular time to carry out a necessary activation of the brake pedal can be generated.
According to one particularly advantageous currently contemplated refinement, this signal or coefficient can be used in an evaluation unit to generate, for example, an acoustic, optical, haptic or similar warning to the driver as a function of the travel situation at a particular time, or of the events on the road detected around the vehicle.
The timing of the generation of the warning can be dependent on the readiness of the driver at a particular time to execute a necessary activation of the brake pedal. Alternatively, or additionally, the warning can be generated as a function of the driver type, which is derived as a further signal variable or coefficient by a relatively long measurement and chronological statistical evaluation or formation of mean values.
Finally, the aforementioned signal or the coefficient can be used to actuate vehicle-mounted vehicle occupant protection and/or driver assistance systems which prevent or reduce an accident. Such systems are equipped with sensors which sense the surroundings, for example video cameras, radar etc. and/or actuators for influencing the lateral movement and/or longitudinal movement for a steering or braking intervention.